The invention disclosed herein relates to filling bottles or similar containers with a fluid wherein the bottle is evacuated, prefilled with an inert or oxygen-free protective gas such as carbon dioxide or nitrogen and then filled with fluid prior to the bottle being sealed. Although the method and device are applicable to a variety of containers, the word "bottles" will be used herein as generic to containers.
A vacuum and protective gas bottle filling machine is described in U.S. Pat. No. 2,808,856. In this known type of device, a protective gas which is displaced by the fluid admitted to the bottles is completely discharged into the atmosphere. With this device, liquids such as wines and hot fruit juices that are oxygen sensitive and foam easily can be bottled without oxygen absorption and without significant foaming. Known filling devices which first evacuate the bottles use great quantities of protective gas because it is discharged into the atmosphere and, thus, used only once. This known process is uneconomical. Furthermore, in prior art devices, the bottles are first filled with a protective gas and are temporarily exposed to atmospheric air pressure before they are filled with liquid. Thus, the protective gas can escape from the bottles and infusion of air into the bottles cannot be ruled out. In order to avoid this effect in the known devices, the ambient atmosphere around the filling devices is filled with inert gas such as nitrogen or carbon dioxide. However, this further increases consumption of protective gases which leak to the atmosphere outside of the filling machine.